Hepatitis A (HAV) has a worldwide distribution. The infection rates are highest in circumstances of poor sanitation and or crowded living conditions. Other high risk groups are children and staff of day care centres and homosexual men. The most common mode of HAV transmissionis through close personal contact, usually by the oral-fecal route.
Transmission by fecally contaminated food and water has been well documented.Unlike Hepatitis B virus (HBV), transmission by blood via parenteral routes is unusual in HAV infection. Most HAV infections are subclinical. AcuteHepatitis secondary to HAV cannot be distinguished from thatsecondary to other viruses. The diagnosis is made by serology.
1) stopping transmission of virus and/or
2) rendering susceptible individuals resistant to infection by active or passive immunization.
HAV vaccine is now the “preferred alternative” for pre-exposure prophylaxis and the National Advisory Committee on Immunization guidelines have been published. Passive immunization with immunoglobulin will continue to be used for post-exposure prophylaxis.